<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>运算符</title>
</head>
<body>

</body>
<!--
运算符大致和java类似，不同点如下：
-->
<script>
//"+"号不同处：
    let num1 = 10;
    let num2 = 20;
    let num3 = "30";
document.write(num1 + num2 + num3+"<br>");//输出3030，10+20结果再与30拼接
document.write(num3 + num2 + num1);//输出302010
//"=="判断值是否相同“===”判断值和类型是否相同
let num4 = "10";
document.write("<br>");
document.write(num1 == num4);//true
document.write("<br>");
document.write(num1 === num4);//false
</script>
</html>